[WIP] Support VirGL

Follow the installation guide from:
https://gitlab.freedesktop.org/virgl/virglrenderer

Prerequisite:
`sudo apt install libepoxy-dev`

Author: shengwen-tw

Makefile

@@ -69,6 +69,16 @@ ifneq ($(UNAME_S),Linux)
     ENABLE_VIRTIOGPU := 0
 endif
 
+# VirGL
+ENABLE_VIRGL ?= 1
+ifeq ($(ENABLE_VIRGL),1)
+    CFLAGS += $(shell pkg-config virglrenderer gl egl epoxy --cflags)
+    LDFLAGS += $(shell pkg-config virglrenderer gl egl epoxy --libs)
+    OBJS_EXTRA += virgl.o
+endif
+
+$(call set-feature, VIRGL)
+
 # SDL2
 ENABLE_SDL ?= 1
 ifeq (, $(shell which sdl2-config))

common.h

@@ -1,5 +1,9 @@
 #pragma once
 
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/uio.h>
+
 #include "feature.h"
 
 #define BITS_PER_CHAR 8
@@ -30,6 +34,12 @@ static inline void bitmap_set_bit(unsigned long *map, unsigned long bit)
     set_bit(bit % BITS_PER_LONG, &map[bit / BITS_PER_LONG]);
 }
 
+size_t copy_iov_to_buf(const struct iovec *iov,
+                       const unsigned int iov_cnt,
+                       size_t offset,
+                       void *buf,
+                       size_t bytes);
+
 /* Range check
  * For any variable range checking:
  *     if (x >= minx && x <= maxx) ...

device.h

@@ -266,8 +266,6 @@ void virtio_gpu_write(hart_t *vm,
                       uint8_t width,
                       uint32_t value);
 
-void semu_virgl_init(virtio_gpu_state_t *vgpu);
-
 void virtio_gpu_init(virtio_gpu_state_t *vgpu);
 void virtio_gpu_add_scanout(virtio_gpu_state_t *vgpu,
                             uint32_t width,

feature.h

@@ -17,6 +17,11 @@
 #define SEMU_FEATURE_VIRTIOGPU 1
 #endif
 
+/* VirGL */
+#ifndef SEMU_FEATURE_VIRGL
+#define SEMU_FEATURE_VIRGL 1
+#endif
+
 /* virtio-input */
 #ifndef SEMU_FEATURE_VIRTIOINPUT
 #define SEMU_FEATURE_VIRTIOINPUT 1

main.c

@@ -11,6 +11,7 @@
 #include "device.h"
 #include "riscv.h"
 #include "riscv_private.h"
+#include "virgl.h"
 #include "window.h"
 
 #define PRIV(x) ((emu_state_t *) x->priv)
@@ -722,19 +723,23 @@ static int semu_start(int argc, char **argv)
     emu.mtimer.mtimecmp = calloc(vm.n_hart, sizeof(uint64_t));
     emu.mswi.msip = calloc(vm.n_hart, sizeof(uint32_t));
     emu.sswi.ssip = calloc(vm.n_hart, sizeof(uint32_t));
-#if SEMU_HAS(VIRTIOGPU)
-    emu.vgpu.ram = emu.ram;
-    virtio_gpu_init(&(emu.vgpu));
-    virtio_gpu_add_scanout(&(emu.vgpu), 1024, 768);
-    window_init();
-#endif
 #if SEMU_HAS(VIRTIOINPUT)
     emu.vkeyboard.ram = emu.ram;
     virtio_input_init(&(emu.vkeyboard));
 
     emu.vmouse.ram = emu.ram;
     virtio_input_init(&(emu.vmouse));
 #endif
+#if SEMU_HAS(VIRTIOGPU)
+    emu.vgpu.ram = emu.ram;
+    virtio_gpu_init(&(emu.vgpu));
+    virtio_gpu_add_scanout(&(emu.vgpu), 1024, 768);
+
+    window_init();
+#endif
+#if SEMU_HAS(VIRGL)
+    semu_virgl_init(&(emu.vgpu));
+#endif
 
     /* Emulate */
     uint32_t peripheral_update_ctr = 0;
@@ -773,6 +778,10 @@ static int semu_start(int argc, char **argv)
                 if (emu.vmouse.InterruptStatus)
                     emu_update_vinput_mouse_interrupts(&vm);
 #endif
+
+#if SEMU_HAS(VIRGL)
+                semu_virgl_fence_poll();
+#endif
             }
 
             emu_update_timer_interrupt(vm.hart[i]);